FIGURE 12-12 Nuclei and Regions of the Hypothalamus (A) Medial view shows the relation between the hypothalamic nuclei and the rest of the brain. (B) Frontal view shows the relative positions of the hypothalamus, thalamus, and—in the midline between the left and right hemispheres—the third ventricle. Note the three principal hypothalamic regions: periventricular, lateral, and medial.